so what's the deal? do those of you who own the rock criterion edition have DTS 2.0 or 5.1? do i need to exchange it for a new printing?

Well... it is The Rock. I think it sneaked into the Collection by mistake.

Maybe just a printing mistake?
I thought DTS IS at least 5.1 channels.

i ain't sure but DTS appears to have most of Dolby's various options in surround sound.
dts:neo cinema=Dolby Pro Logic IIx cinema/Pro Logic variety etc.
dts:neo music=Dolby Pro Logic IIx music
dts2.0=Dolby Digital 2.0/Dolby Pro Logic Wide (3 ch. only).
dts5.1=Dolby Digital 5.1
dts-ES 6.1Matrix=Dolby Digital EX 6.1

Dolby doesn't have is the equivalent of DTS-ES 6.1 Discrete and the things that dts doesn't have are the various other Dolby codecs such as Dolby Digital 1.0 (mono for classic b&w films), Dolby Digital 4.0, etc.

thus, the listing on the criterion DVD is wrong, it lists 5.1 but is only actually 2.0 with the center matrixing the dialogue from the 2.0.

DTS appears to have most of Dolby's various options in surround sound.
dts:neo cinema=Dolby Pro Logic IIx cinema/Pro Logic variety etc.
dts:neo music=Dolby Pro Logic IIx music
dts2.0=Dolby Digital 2.0/Dolby Pro Logic Wide (3 ch. only).
dts5.1=Dolby Digital 5.1
dts-ES 6.1Matrix=Dolby Digital EX 6.1

I didn't know those. Thanks for clearing that up.

i think that most DVD players can also playback other types of DVD spex. Dolby Digital 3.0, 4.0 and 5.0 are all fairly common. i think DTS 5.0 exists but i'm not sure about DTS 3.0, 4.0, etc.

in the future, DTS-HD, Dolby Digital HD and "TrueHD" are all coming offering backwards compatibility and higher resolutions.